Method of lowering pour points of mineral oils



Patented May 11, 1937 aosonss 1 METHOD JOE LOWERING POUR POINTS 01MINERAL OILS Franz Rudolf Moser, Amsterdam, Netherlands, assignor toShell Development Company, San Francisco, Calif., a corporation ofDelaware No Drawing. Application October 25, 1933, Serial In theNetherlands November 2,

'13 Claims. (01. 196-1) The invention relates to a process for reducingpour points of hydrocarbon oils, particularly of lubricating oils.

It has been found that the pour point of vis- 5 cous hydrocarbon oilscan be lowered by adding polymerized Edeleanu extracts and similarextracts of'mineral oils. By polymerized Edeleanu extracts and the likeare meant Edeleanu'extracts or other'extracts rich in non-paraflinichydrocarbons obtained by extraction of mineral oils with solvents, suchas furfural, phenol, nitrobenzene, BB'dichloroethyl ether (chlorex),etc.', which. extracts have been cracked or exposed to heating in thepresence or absence of catalysts 55 and have thereby acquired pourpoint-reducing properties. tracts were found to be far more effective aspour point-reducers, or as sources of pour pointreducing substances,derived in the manner here- 90 inafter disclosed, than any othercracked'oils,

tars, residues or pitches. In principle, any extract can be used, but asa rule extracts of lubri cating oils are to be preferred in view oftheir better yield of polymerization products.

Inthe application of polymerized extracts for lowering the pour pointsof lubricating oils, which, for example, have high pour points by reasonof their high paraffin wax contents, difficulties are often encountered.due to the fact 0 that these extracts do not dissolve readily in the oiland sometimes have an unfavourable efiect on the colour of thelubricating oils. 7

It has now been found that these drawbacks do not occur when thecomponents of the darkest colour and least soluble in hydrocarbons poorin aromatics are first separated from the polymerization product bymeans of precipitating agents in which these components are insoluble.

A highly suitable precipitating agent is a kero- 40 sene poor inaromatics, while lighter'distillates, such as straight run gasoline poorin aromatics, may also be used, as well as a lubricating oil poor inaromatics. suitable for precipitation of undesirable darkcolouredsubstances, such as mixtures of alcohol and ether, ethyl acetate andamyl alcohol.

' In some cases the use of a lubricating oil poor in aromatics asprecipitating agent may have its advantages.

lighterdistillate is used as precipitating agent the resulting diluteoil solution usually has to be concentrated by distillation (with steamor under vacuum, if desired) and the resultant residue applied, as suchor dissolved in oil, as a Such activated or polymerized ex Many otherliquids are also For example, when kerosene or a pour point-reducingagent; howevenwhen a lubricating oil poor in aromatics is used as theprecipitating agent the resulting oil solution can be added directly tothe oil whose pour point is to be reduced. The effective quantity to beused in each case can be readily ascertained by tests.

In many cases it may be considered preferable to add the polymerizedEdeleanu extract treated in the above manner in the form of a solution,so as tofacilitate dosing. For. instance, if the pour point of alubricating oil has to be reduced, then a similar lubricating oil mayalso be used as a solvent for diluting the polymerized extract freed ofthe undesirable dark coloured substances.

By choosing the right precipitating agent and by regulating its quantityand the treating temperature, it may be assured that substantially onlyundesirable components are removed from the oil, i. e. those which areleast soluble and darkest in colour. These undesirable components, whichare removed in the described manner, may be referred to as an asphaltenefraction. Therefore, it is the least soluble and darkest colouredasphaltenes that are removed from the polymerized Edeleanu extract andthe like, thus leaving the so-called maltenes and the. lighter colouredasphaltenes dissolved in the precipitating agent. The remaining, i. e.not precipitated, portion (further concentrated or not) of thepolymerized extract may be referred to as the active portion of suchextracts.

Before applying the above described refining treatment to thepolymerized Edeleanu extract and the like, these materials may beconcentrated by distilling off more volatile components (with steam orunder vacuum, if desired, so as to avoid cracking at this stage) and/orreheated, thereby increasing the content of pour point-reducingcomponents. The reheating can be done, for instance, at a mild crackingtemperature, such as about 350 C.

The active pour point-reducing substances may be concentrated in therafiinate obtained by distillingofi morevolatile components from saidrafiinate substantially without causing the cracking of the resultingdistillation residue. The raflinate may be further activated byreheating same substantially without distillation or cracking e. g. byprolonged heating at a temperature of about 350 C.

Example tion, was heated for 4 hours to 400 C. under a pressure of about5 atmospheres. The polymerization product, which was obtained with ayield of was concentrated by steam distillation to a residue of 15-20%calculated on the original extract; it had the appearance of a hardasphalt or pitch. This residue was mixed at about C. with 2 volumes ofkerosene containing about 8% aromatics. After being cooled, the solutionwas decanted (it could be filtered) and the kerosene evaporated withsteam. The resulting residue (6% of original extract) was the desiredproduct which was used for reducing pour points of mineral oils.

When this product was added to three different lubricating oils withpour points 0 C., +1 C. and -6 C. in proportion of 1%, the pour pointswere reduced by 12, 10 and 9 C., respectively.

In order to obtain a liquid product, a suitable quantity of alubricating oil can be added before evaporating the kerosene or otherprecipitant; the distillation (carried out at non-cracking temperatures)is so controlled then as not to distil off the added lubricating oil, sothat it remains in the residue and the final product (residue) isobtained in the liquid form.

Instead of a kerosene also a lubricating oil fraction poor in aromaticscan be used as the precipitating agent, such, for instance, as anEdeleanu raffinate, which may have been treated with an acid. Afterfiltering or centrifuging the resulting product can be used directly asa pour point-reducing agent.

I claim as my invention:

1. In the process of lowering the pour point of a mineral oil, the stepsof precipitating asphaltenes from a polymerized extract derived byextracting mineral oil with a selective solvent for non-parafiinichydrocarbons by adding a liquid precipitant for asphaltenes to saidpolymerized extract, removing the precipitate and the precipitant fromthe unprecipitated portion, thereby concentrating active pourpoint-reducing substances in the unprecipitated portion, and adding thesaid concentrated pour point-reducing substances to the mineral oil.

2. The method of lowering the pour point of a viscous mineral oil, whichcomprises the step of incorporating into said oil an eifective quantityof a polymerized S02 soluble mineral oil extract rich in non-parafiinichydrocarbons, substantially free from substances which are insoluble inlight saturated aliphatic hydrocarbons.

3. In the process for preparing pour point reducing substances, thesteps or" adding a liquid precipitant for asphaltenes to a polymerizedS02 soluble mineral oil extract rich in non-parafiinic hydrocarbons,thereby dissolving a portion of said polymerized extract in theprecipitant and precipitating asphaltenes from the dissolved portion,and separating the precipitate from the unprecipitatedportion of thepolymerized extract.

4. The process according to claim 3, in which the liquid precipitant isa light hydrocarbon rich in saturated aliphatic hydrocarbons.

5. The process according to claim 3, in which the liquid precipitant isa lubricating oil which is poor in aromatics.

6. The process according to claim 3, in which the liquid precipitant isa mixture ofv alcohol and ether.

'7. In the process for preparing pour point re ducing substances, thesteps of adding a liquid precipitant for asphaltenes to a polymerizedS02 soluble mineral oil extract rich in non-parafilnic hydrocarbons,thereby dissolving a portion of said polymerized extract in theprecipitant and precipitating asphaltenes from the dissolved portion,separating the precipitate from the solution of precipitant andunprecipitated polymerized extract, separating the precipitant from theunprecipitated portion of the polymerized extract by distillation, andthen distilling oil the relatively more volatile components of saidunprecipitated portion substantially without causing the cracking of theresulting distillation residue, thereby concentrating active pour pointreducing substances in said residue.

8. In the process for preparing pour point reducing substances, thesteps of adding a liquid precipitant for asphaltenes to a polymerizedS02 soluble mineral oil extract rich in non-parafllnic hydrocarbons,thereby dissolving a portion of said polymerized extract in theprecipitant and precipitating asphaltenes from the dissolved portion,separating the precipitate from the solution of the precipitant andunprecipitated portion of the polymerized extract, removing said precipitant from said solution by distillation, and activating the resultingunprecipitated portion of the polymerized extract by heating the same at1 about 350 C.

9. In the process for preparing pour point reducing substances from apolymerized S02 soluble hydrocarbon oil extract containing the same, thesteps of concentrating said polymerized extract rich in non-parafiinichydrocarbons by distilling it to remove the relatively more volatilecomponents, adding a liquid precipitant for asphaltenes to the resultingdistillation residue, thereby dissolving a portion of said residue inthe precipitant and precipitating asphaltenes from the dissolvedportion, and separating the precipitate from the unprecipitated portionof said distillation residue.

10. In the process for preparing pour pointreducing substances, thesteps of adding a hydrocarbon fraction which is poor in aromatic hydro-.

carbons to a pyrogenous polymerization product of an S02 soluble mineraloil extract rich in non-parafiinic hydrocarbons, thereby dissolving aportion of said polymerization product and precipitating asphaltenes,and removing the precipitate from the unprecipitated portion of thepolymerization product.

11. As a new composition, a Wax-bearing lubricating oil containing theasphaltene-free portion of a polymerized liquid sulfur dioxide solubleextract from mineral oil.

' 12. As a new composition, a wax-bearing lubricating oil containingthat portion of polymerized S02 soluble mineral oil extractwhich issoluble in light saturated aliphatic hydrocarbons, and substantiallyfree from substances which are insoluble in light, saturated aliphatichydrocarbons.

13. As a new composition, a wax-bearing lubricating oil containing thatportion of a pyrogenous condensation product of S02 soluble mineral oilextract which is soluble in light saturated aliphatic hydrocarbons, andsubstantially free from substances which are insoluble in lightsaturated aliphatic hydrocarbons.

FRANZ RUDOLF MOSER.

